ABSTRACT
Background: Polyethylene glycols (PEGs), also called macrogols, are molecules that cause allergic reactions in individuals who are sensitized to them. Their relevance lies in their popularity as they are usually found in many drugs and skin products such as laxatives, cosmetics, antibiotics, corticoids, contrast dyes, vitamin complexes These compounds have recently attained certain prominence due to their presence in several vaccines developed against the global pandemic of SARS-CoV2. Allergic to these substances individuals cannot be vaccinated, as PEGs or polysorbate 80 (which cross-reacts with PEGs) may be included in the vaccine. This research presents a clinical case of a 57-year man who had had several local skin reactions with associated itching, caused by different cosmetic products and Betadine® (povidone-iodine ointment) in gel. He also developed a similar clinical picture, as well as wheezing, by means of Moviprep® (a laxative), but the same day he tolerated another laxative, Casenglicol®. Additionally, he suffered a reaction to Vincigrip® (paracetamol/pseudoephedrine hydrochloride/chlorpheniramine maleate), but tolerated paracetamol alone Method: The tests have been practised on this patient are standard patch-tests, photopatch testing with sunscreen lotions, prick-tests and intra dermo-reaction (1:100) with PEGs, and controlled exposure test with laxatives Citraflett® and Vincigrip® (both of them without PEGs). Results: All these tests cast negative results but the intra dermoreaction test. In this case, the patient developed facial and oropharynx itchiness, scattered wheals, and dyspnoea, which decreased after administrating adrenaline, corticoids, and antihistamines. The patient was diagnosed allergy to PEG and has been advised from receiving any SARS-CoV2 vaccine at all. Conclusion: It is of great relevance to diagnose allergic to PEG patients, for two main reasons. First, due to the frequent presence of PEGs in medicaments and cosmetics. Many times they may be overlooked as they are included only in some formulations or brands of a same product. Thus, in consequence, these patients cannot be administrated some vaccines against SARS-CoV2 containing PEG or polysorbate.